Agrotis segetum雄蛾触角叶性信息素反应神经元对电刺激触角神经的反应

为探讨电刺激Agrotis segetum雄蛾触角神经是否可以作为MGC中神经元的识别手段,采用细胞内电生理记录方法,共记录34个对性信息素有反应的MGC神经元,并测试了其中12个神经元对性信息素刺激的反应,22个神经元对性信息素刺激和电刺激的反应。结果表明,MGC神经元对性信息素及电刺激的反应模式基本一致,为一种双相反应模式。两种刺激方式均能诱导出兴奋反应,电刺激得到的兴奋反应比由信息素刺激引起的要短;MGC神经元对两种刺激的超极化反应（抑制反应）幅度影响没有显著性差别,在电刺激实验的22个神经元上,超极化反应幅度和抑制时间都与神经元本身放电频率有一定的相关性。超极化反应是在LN参与下一定的神经回路对刺激所产生的反应而形成的。这提示两种刺激所作用的神经回路应是一致的,但从整个实验过程记录到的神经元情况来看,还须进一步结合形态学实验来验证电刺激触角神经作为MGC神经元的识别手段。     

Honey bee (Hymenoptera: Apidae) foraging in response to preconditioning with onion flower scent compounds

Onion (Allium cepa L.) seed production has long been plagued with yield problems because of lack of pollination by the honey bee, Apis mellifera L. To attempt to attract more pollinators to the onion seed production field, honey bees were conditioned to associate onion floral odor components with a reward. Isolated nucleus hives of honey bees were fed 30% sucrose solutions scented with a 0.2% solution of onion floral odor compounds. After feeding on these solutions for 6 wk, bees were not found to prefer onion flowers to two competing food sources, carrot and alfalfa flowers, at the 5% significance level. However, there was an overall trend indicating a change in honey bee behavior, with fewer "trained" bees visiting alfalfa and carrot and more visiting onion. Thus, it may be possible to alter honey bee behavior with preconditioning but probably not to a degree that would be economically significant.     

G-protein coupled receptor solubilization and purification for biophysical analysis and functional studies,in the total absence of detergent

G-protein coupled receptors (GPCRs) constitute the largest class of membrane proteins and are a major drug target. A serious obstacle to studying GPCR structure/function characteristics is the requirement to extract the receptors from their native environment in the plasma membrane, coupled with the inherent instability of GPCRs in the detergents required for their solubilization. In the present study, we report the first solubilization and purification of a functional GPCR [human adenosine A_2A receptor (A_2AR)], in the total absence of detergent at any stage, by exploiting spontaneous encapsulation by styrene maleic acid (SMA) co-polymer direct from the membrane into a nanoscale SMA lipid particle (SMALP). Furthermore, the A_2AR–SMALP, generated from yeast (Pichia pastoris) or mammalian cells, exhibited increased thermostability (∼5°C) compared with detergent [DDM (n-dodecyl-β-D-maltopyranoside)]-solubilized A_2AR controls. The A_2AR–SMALP was also stable when stored for prolonged periods at 4°C and was resistant to multiple freeze-thaw cycles, in marked contrast with the detergent-solubilized receptor. These properties establish the potential for using GPCR–SMALP in receptor-based drug discovery assays. Moreover, in contrast with nanodiscs stabilized by scaffold proteins, the non-proteinaceous nature of the SMA polymer allowed unobscured biophysical characterization of the embedded receptor. Consequently, CD spectroscopy was used to relate changes in secondary structure to loss of ligand binding ([³H]ZM241385) capability. SMALP-solubilization of GPCRs, retaining the annular lipid environment, will enable a wide range of therapeutic targets to be prepared in native-like state to aid drug discovery and understanding of GPCR molecular mechanisms.     

Clinical Characteristics and Outcomes in Patients with Pulmonary Blastomycosis

Background  Blastomycosis is an uncommon granulomatous infection caused by the thermally dimorphic fungus Blastomyces dermatitidis. The most frequent clinical infections involve the lung, skin, and bone. Pulmonary manifestations range from asymptomatic self-limited infection to severe diffuse pneumonia causing respiratory failure. Objectives  To establish the clinical characteristics and outcomes of patients with pulmonary blastomycosis diagnosed at hospitals in Manitoba and northwestern Ontario, Canada. Methods  A retrospective review of medical records was done for 318 patients with blastomycosis in these regions. Results  The majority of patients were Caucasian (198 (62.5%) patients), male (193 (61%) patients), and residents of Ontario (209 (65.7%) patients). Most patients were treated in an inpatient hospital ward (266 (84%) patients) and survived (294 (92%) patients). Pulmonary involvement, either alone or associated with other sites, was present in 296 (93%) of the 318 patients; 22 (7%) patients had no evidence of pulmonary blastomycosis. The majority of patients had localized lung disease (1–3 quadrants on chest radiograph involved; 225 (82%) patients). Of 294 (92%) patients requiring hospitalization, 266 (90%) patients received all inpatient care on a general medical ward; 28 (10%) patients received some care in the intensive care unit (ICU). Factors associated with ICU admission included diffuse pulmonary disease (four quadrants involved on chest radiograph), diabetes, and prior use of antimicrobial therapy. Twenty-four (8%) patients died, and multivariate analysis showed that older age and Aboriginal ethnicity were the significant risk factors for death from blastomycosis. Conclusion  Blastomycosis is a cause of serious, potentially life-threatening pulmonary infection in this geographic region. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Sorting nexin 27 interacts with the Cytohesin associated scaffolding protein (CASP) in lymphocytes

CASP is a small cytokine-inducible protein, primarily expressed in hematopoetic cells, which associates with members of the Cytohesin/ARNO family of guanine nucleotide-exchange factors. Cytohesins activate ARFs, a group of GTPases involved in vesicular initiation. Functionally, CASP is an adaptor protein containing a PDZ domain, a coiled-coil, and a potential carboxy terminal PDZ-binding motif that we sought to characterize here. Using GST pulldowns and mass spectrometry we identified the novel interaction of CASP and sorting nexin 27 (SNX27). In lymphocytes, CASP's PDZ-binding motif interacts with the PDZ domain of SNX27. This protein is a unique member of the sorting nexin family of proteins, a group generally involved in the endocytic and intracellular sorting machinery. Endogenous SNX27 and CASP co-localize at the early endosomal compartment in lymphocytes and also in transfection studies. These results suggest that endosomal SNX27 may recruit CASP to orchestrate intracellular trafficking and/or signaling complexes.     

ASSOCIATION OF α-AMYLASE WITH CELLULAR AUTOLYSIS IN PEA STEM TISSUES

Increased activity of α-amylase in bean stems occurred during cellular autolysis in the pith region. In etiolated pea seedlings, α-amylase activity increased sequentially in the first, second, and third internodes. In light-grown seedlings, the increase was initially observed in the first internode, then simultaneously in the second and third internodes. In all internodes, these changes were observed in regions undergoing cellular autolysis in the cortex region. As in bean hypocotyls, α-amylase activity occurred in tissues virtually devoid of starch. Sequential accumulation and then decline in protein and sugar concentrations in each internode indicate a remobilization of materials from nongrowing regions of the stem. These results are consistent with the hypothesis that regulation of α-amylase activity is related to this remobilization.